Percutaneous electrode assemblies, systems, and methods for providing highly selective functional or therapeutic neuromuscular stimulation

ABSTRACT

Percutaneous electrode assemblies, systems, and methods make possible the providing of short-term therapy or diagnostic testing by providing electrical connections between muscles or nerves inside the body and stimulus generators or recording instruments carried outside the body. The percutaneous electrodes include a flexible body having an electrically conductive region, a tissue penetrating region, and a percutaneous lead electrically coupled to the electrically conductive region. An anchoring element is positioned on the flexible body to resist movement of the electrically conductive region within tissue. An introducer is sized and configured to receive the flexible body and shield the anchoring element from contact with tissue while the electrically conductive region is placed to a desired position within tissue, and accommodates advancement of the anchoring element beyond the interior lumen for contact with tissue to resist movement of the electrically conductive region placed in the desired position.

RELATED APPLICATION

This application is a continuation of application Ser. No. 11/545,336filed 10 Oct. 2006 which is a divisional application of U.S. patentapplication Ser. No. 10/777,771, filed 12 Feb. 2004, and entitled“Portable Percutaneous Assemblies, Systems, and Methods for ProvidingHighly Selective Functional Therapeutic Neuromuscular Stimulation.”

FIELD OF INVENTION

This invention relates to percutaneous electrode systems and methods forproviding neuromuscular stimulation.

BACKGROUND OF THE INVENTION

Neuromuscular stimulation can perform functional and/or therapeuticoutcomes. While existing systems and methods can provide remarkablebenefits to individuals requiring neuromuscular stimulation, manyquality of life issues still remain. For example, existing systemsperform a single, dedicated stimulation function. Furthermore, thesecontrollers are, by today's standards, relatively large and awkward tomanipulate and transport.

It is time that systems and methods for providing neuromuscularstimulation address not only specific prosthetic or therapeuticobjections, but also address the quality of life of the individualrequiring neuromuscular stimulation.

SUMMARY OF THE INVENTION

The invention provides improved percutaneous electrode assemblies,systems, and methods for providing prosthetic or therapeuticneuromuscular stimulation.

One aspect of the invention provides portable, percutaneousneuromuscular stimulation assemblies, systems and methods that provideelectrical connections between muscles or nerves inside the body andstimulus generators or recording instruments temporarily mounted on thesurface of the skin outside the body. The assemblies, systems, andmethods are, in use, coupled by percutaneous leads to electrodes, whichare implanted below the skin surface in a targeted tissue region orregions. The neuromuscular stimulation assemblies, systems, and methodsapply highly selective patterns of neuromuscular stimulation only to thetargeted region or regions, to achieve one or more highly selectivetherapeutic and/or diagnostic outcomes. The patterns can vary accordingto desired therapeutic and/or diagnostic objectives. The indications caninclude, e.g., the highly selective treatment of pain or muscledysfunction, and/or the highly selective promotion of healing of tissueor bone, and/or the highly selective diagnosis of the effectiveness of aprospective functional electrical stimulation treatment by a future,permanently implanted device.

The neuromuscular stimulation assemblies, systems, and methods comprisea skin-worn patch or carrier. The carrier can be readily carried, e.g.,by use of a pressure-sensitive adhesive, without discomfort and withoutaffecting body image on an arm, a leg, or torso of an individual.

The carrier carries an electronics pod, which generates the desiredelectrical current patterns. The pod houses microprocessor-based,programmable circuitry that generates stimulus currents, time orsequence stimulation pulses, and logs and monitors usage. Theelectronics pod also includes an electrode connection region, tophysically and electrically couple percutaneous electrode leads to thecircuitry of the electronics pod.

The carrier further includes a power input bay, to receive a small,lightweight, primary cell battery, which can be released and replaced asprescribed. The battery provides power to the electronics pod.

It is contemplated that, in a typical regime prescribed using theneuromuscular stimulation assemblies, systems, and methods, anindividual will be instructed to regularly remove and discard thebattery (e.g., about once a day or once a week), replacing it with afresh battery. This arrangement simplifies meeting the power demands ofthe electronics pod. The use of the neuromuscular stimulationassemblies, systems, and methods thereby parallels a normal, accustomedmedication regime, with the battery being replaced at a prescribedfrequency similar to an individual administering a medication regime inpill form.

The power input bay can also serve as a communication interface, to beplugged into a mating communications interface on an external device.Through this link, a caregiver or clinician can individually program theoperation of a given electronics pod.

The assemblies, systems, and methods make possible many differentoutcomes, e.g., (i) acute pain relief through treatment of pain ormuscle dysfunction via the application of electrical stimulation tomuscles (or their enervating nerves) with compromised volitional controldue to injury to the peripheral or central nervous system (e.g., limbtrauma, stroke, central nervous system diseases, etc.); and/or (ii)maintenance of muscle function and prevention of disuse atrophy throughtemporary stimulation to maintain muscle strength, mass, peripheralblood flow, etc, following a temporary disruption of function by diseaseor injury; and/or (iii) enhanced tissue and bone regeneration throughthe provision of small DC currents (or very low frequency AC currents)in bone or tissue to aid or speed healing of bone unions, tissuere-growth, etc; and/or (iv) treatment of pain or other conditionsthrough the application of nerve stimulation to provide aneuromodulation or inhibitory effect; and/or (v) post-surgicalreconditioning to enhance muscle function and promote recovery ofstrength post-operatively; and/or (vi) anti-thrombosis therapy, e.g., bythe stimulation of leg muscles to increase venous return of blood;and/or (vii) the treatment of osteoporosis by cyclic stimulation ofmuscles; and/or (viii) the short-term provision of electricalstimulation to evaluate the effectiveness of such treatment in advanceof the implantation of a more permanent implant; and/or (ix) theshort-term recording of biopotential signals generated in the body toaid in the diagnosis of medical conditions or in the assessment of theeffectiveness of treatment methods.

Another aspect of the invention provides systems and methods forimplanting a percutaneous electrode having an electrically conductiveregion. The systems and methods provide a percutaneous electrode with ananchoring element to resist movement of the percutaneous electrodewithin tissue. The systems and methods insert the percutaneous electrodethrough skin and tissue housed within an introducer, which shields theanchoring element from contact with tissue. The introducer may includean electrically isolated area that corresponds to the electricallyconductive region of the electrode. The electrically isolated area maythen be electrically coupled to a connector on the introducer to allowthe electrically isolated area to be coupled to a stimulating circuit.

The systems and methods implant the percutaneous electrode whileinserted within the introducer, to place the percutaneous electrode in adesired location within tissue, but without placing the anchoringelement in contact with tissue. The systems and methods withdraw theintroducer to place the anchoring element in contact with tissue,thereby resisting movement of the percutaneous electrode from thedesired position. The systems and methods may also include, during theimplanting step, a step of coupling the percutaneous electrode to astimulating circuit to provoke a tissue stimulation response to placethe percutaneous electrode in the desired location. Or, during theimplanting step, the systems and methods may also include a step ofcoupling the introducer to a stimulating circuit to provoke a tissuestimulation response to place the percutaneous electrode in the desiredlocation.

One aspect of the invention provides a flexible body that is sized tohave a diameter not greater than about 0.5 mm, and an anchoring elementthat comprises a barb.

Yet another aspect of the invention provides a percutaneous electrodeassembly having a flexible body including one or more electricallyconductive regions, a tissue penetrating region for implantation of theelectrically conductive regions in a targeted tissue region, and apercutaneous lead electrically coupled to the electrically conductiveregions, the lead including a conductor for each electrically conductiveregion. An anchoring element is positioned on the flexible body toresist movement of the electrically conductive region within tissue. Aflexible introducer that has an interior lumen is sized and configuredto receive the flexible body and shield the anchoring element fromcontact with tissue while the electrically conductive region is placedto a desired position within tissue. The flexible introducer is alsosized and configured to accommodate advancement of the anchoring elementbeyond the interior lumen for contact with tissue to resist movement ofthe electrically conductive region placed in the desired position. Theflexible introducer may also be sized and configured to accommodateadvancement of the flexible body and anchoring element beyond theinterior lumen while the flexible introducer is bent.

Other features and advantages of the inventions are set forth in thefollowing specification and attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a neuromuscular stimulation assemblythat provides electrical connections between muscles or nerves insidethe body and stimulus generators temporarily mounted on the surface ofthe skin outside the body.

FIG. 2 is a view of the neuromuscular stimulation assembly shown in FIG.1 worn on a temporary basis on an external skin surface of an arm.

FIG. 3 is an exploded side view of the neuromuscular stimulationassembly shown in FIG. 1, showing its coupling to percutaneous leads toelectrodes, which are implanted below the skin surface in a targetedtissue region or regions.

FIGS. 4A and 4B are perspective views of an electronics pod that isassociated with the neuromuscular stimulation assembly shown in FIG. 1,which is capable of being docked within an electronics bay in theneuromuscular stimulation assembly for use, with FIG. 4A showing the podin a closed condition for docking with neuromuscular stimulationassembly, and FIG. 4B showing the pod in an opened condition forreceiving electrode leads prior to docking with the neuromuscularstimulation assembly.

FIG. 5 is a perspective view of an electronics pod as shown in FIG. 4Adocked within an electronics bay in a neuromuscular stimulation assemblyfor use, showing the power input bay opened and empty to enable visualinspection of underling skin.

FIG. 6 is a perspective view of the electronics pod shown in FIG. 4B inan opened condition on a skin surface preliminary to placement ofpercutaneous electrodes.

FIGS. 7 and 8 show the implantation of a first percutaneous electrode(FIG. 7) and the routing of its percutaneous electrode lead into anelectrode connection region on pod (FIG. 8).

FIG. 9 shows the presence of second, third, and fourth percutaneouselectrodes that have been sequentially implanted and the routing oftheir percutaneous electrode leads into the electrode connection regionson the pod, while the pod remains in the opened condition.

FIG. 10 shows the pod shown in FIG. 9, after having been placed in aclosed condition, ready for use.

FIG. 11 shows the pod shown in FIG. 10, after having been docked withinan electronics bay in the neuromuscular stimulation assembly for use.

FIGS. 12A and 12B are perspective views of an alternative embodiment ofa neuromuscular stimulation assembly, which includes an integratedelectronics pod, with FIG. 12A showing the neuromuscular stimulationassembly in a closed condition for use, and FIG. 12B showing theneuromuscular stimulation assembly in an opened condition for receivingelectrode leads prior to use.

FIG. 13 is a perspective view of a neuromuscular stimulation assembly ofthe type shown in FIG. 1 coupled to an external programming instrument.

FIGS. 14 to 16 show the use of an electrode introducer to percutaneouslyimplant an electrode in the manner shown in FIGS. 6 and 7 for connectionto a neuromuscular stimulation assembly as shown in FIG. 11.

FIG. 17 is a perspective view of a neuromuscular stimulation systemcomprising a neuromuscular stimulation assembly of the type shown inFIG. 1 in association with a prescribed supply of replacement batteriesand instructions for using the a neuromuscular stimulation assembly,including the recharging of the neuromuscular stimulation therapy byinserting a fresh battery, just as an individual on a medication regime“recharges” their medication therapy by taking a pill.

The invention may be embodied in several forms without departing fromits spirit or essential characteristics. The scope of the invention isdefined in the appended claims, rather than in the specific descriptionpreceding them. All embodiments that fall within the meaning and rangeof equivalency of the claims are therefore intended to be embraced bythe claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The various aspects of the invention will be described in connectionwith providing functional neuromuscular stimulation for prosthetic ortherapeutic purposes. That is because the features and advantages thatarise due to the invention are well suited to this purpose. Still, itshould be appreciated that the various aspects of the invention can beapplied to achieve other objectives as well.

I. Neuromuscular Stimulation Assembly 10

A. Overview

FIG. 1 shows a neuromuscular stimulation assembly 10. As FIG. 2 shows,the neuromuscular stimulation assembly 10 is sized and configured sothat, in use, it can be conveniently worn on a temporary basis on anexternal skin surface. By “temporary,” it is meant that the presence ofthe neuromuscular stimulation assembly 10 can be well tolerated withoutdiscomfort for a period of time from several hours to a month or two,after which the neuromuscular stimulation assembly 10 can be removed anddiscarded.

As FIG. 3 shows, the neuromuscular stimulation assembly 10 is, in use,releasably coupled by percutaneous leads 12 to electrodes 14, which areimplanted below the skin surface in a targeted tissue region or regions.The tissue region or regions are targeted prior to implantation of theelectrodes 14 due to their muscular and/or neural morphologies in lightof desired therapeutic and/or functional and/or diagnostic objectives.

In use, the neuromuscular stimulation assembly 10 generates anddistributes electrical current patterns through the percutaneous leads12 to the electrodes 14. In this way, the neuromuscular stimulationassembly 10 applies highly selective patterns of neuromuscularstimulation only to the targeted region or regions, to achieve one ormore highly selective therapeutic and/or diagnostic outcomes. As will bedescribed in greater detail later, the inputs/stimulation parameters canvary according to desired therapeutic and/or diagnostic objectives. Forexample, the outcomes can comprise the highly selective treatment ofpain or muscle dysfunction, and/or the highly selective promotion ofhealing of tissue or bone, and/or the highly selective diagnosis of theeffectiveness of a prospective functional electrical stimulationtreatment.

B. The Carrier

In its most basic form (see FIGS. 1 and 3), the neuromuscularstimulation assembly 10 comprises a patch or carrier 16. The carrier 16desirably is sized and configured as a compact, lightweight housingmade, e.g., of an inert, formed or machined plastic or metal material.

In a desired implementation, the carrier 16 approximates the geometry ofthe face of a wrist watch, measuring, e.g., about 1 inch in diameter,weighing, e.g., about 5 g. At this size, the carrier 16 can be readilyworn without discomfort and in a cosmetically acceptable way (as FIG. 2shows). The carrier 16 physically overlays and protects the site wherethe percutaneous electrode leads 12 pass through the skin.

Within its compact configuration, the carrier 16 includes severalfunctional components, which will now be described.

C. The Adhesive Region

At least a portion of the undersurface of the carrier 16 (see FIGS. 1and 3) includes an adhesive region 18. The function of the adhesiveregion 18 is to temporarily secure the carrier 16 to an external skinsurface during use. For example, an inert, conventional pressuresensitive adhesive can be used. Desirably, the adhesive region containsa bacteriostatic sealant that prevents skin irritation or superficialinfection, which could lead to premature removal.

The adhesive region 18 can also include an electrically conductivematerial. In this arrangement, the adhesive region 18 can serve as areturn electrode, so that monopolar electrodes 14 can be implanted, ifdesired.

D. The Electronics Pod

The carrier 16 further carries an electronics pod 20, which generatesthe desired electrical current patterns.

As FIG. 3 shows, the electronics pod 20 can comprise a component thatcan be inserted into and removed from an electronics bay 22 in thecarrier 16. Having an electronics pod 20 that can be separated from thecarrier 16 may be desired when the need to replace a carrier 16 during acourse of treatment is necessary. For example, replacement of a carrier16 without replacement of the electronics pod 20 may be desired if theanticipated length of use of the neuromuscular stimulation assembly 10is going to be long enough to expect a degradation of adhesiveproperties of the adhesive region 18, or when the adhesive region 18serves as a return electrode and may undergo, with use, degradation ofadhesive properties and/or electrical conductivity.

Alternatively, as FIGS. 12A and 12B show, the electronics pod 20 cancomprise an integral, non-removable part of the carrier 16.

Regardless of whether the electronics pod 20 is removable from thecarrier 16 (FIGS. 4A and 4B) or not (FIGS. 12A and 12B), the pod 20houses microprocessor-based circuitry 24 that generates stimuluscurrents, time or sequence stimulation pulses, and logs and monitorsusage. The circuitry 24 desirably includes a flash memory device or anEEPROM memory chip to carry embedded, programmable code 26. The code 26expresses the pre-programmed rules or algorithms under which thestimulation timing and command signals are generated. The circuitry 24can be carried in a single location or at various locations on the pod20.

E. The Electrode Connection Region

As FIGS. 4A/4B and FIGS. 12A/12B show, the electronics pod 20 alsoincludes an electrode connection region 28. The function of theelectrode connection region 28 is to physically and electrically couplethe terminus of the percutaneous electrode leads 12 to the circuitry 24of the electronics pod 20 (as FIG. 10 shows). The electrode connectionregion 28 distributes the electrical current patterns in channels—eachelectrode 14 comprising a channel—so that highly selective stimulationpatterns can be applied through the electrodes 14. Four channels(numbered 1 to 4 on the pod 20) are shown in FIGS. 4A/4B and 12A/12B.

The electrode connection region 28 can be constructed in various ways.In the illustrated embodiments FIGS. 4A/4B and FIGS. 12A/12B), theelectrode connection region 28 comprises troughs 30 formed in theelectronics pod 20. Four troughs 30 are shown in FIGS. 4A/4B and FIGS.12A/12B, each trough 30 being sized and configured to slidably receivethe lead 12 of one electrode 12 in an interference fit (see FIG. 10).Each trough 30 is labeled with a number or other indicia to record thechannel of the electronics circuitry 24 that is coupled to each trough30.

Each trough 30 routes the terminus of an electrode lead 12 to a givenchannel (see FIG. 7), allowing the lead 12 to be stretched taut tobecome frictionally lodged within the trough 30. In FIGS. 4A/4B, thetrough 30 includes at its end a mechanism 60 to displace or pierce theinsulation of the lead and make electrical contact with the conductivewire of the lead 12. This mechanically secures the lead 12 whileelectrically coupling the associated electrode 14 with the circuitry 24of the electronics pod 20.

In the illustrated embodiment, for ease of installation, the electronicspod 20 shown in FIGS. 4A and 4B comprises mating left and right podsections 32 and 34 joined in a sliding fashion by rails 36. The podsections 32 and 34 can be separated by sliding apart along the rails 36to an opened condition, as shown in FIG. 4B. The pod sections 32 and 34can brought together by sliding along the rails 36 to a closedcondition, as shown in FIG. 4A. The electronics circuitry 24 is carriedwithin one or both of the pod sections 32 and 34.

When in the opened position (see FIG. 6), the separated pod sections 32and 34 expose a region 38 of underlying skin through which theelectrodes 14 can be percutaneously implanted. The implantation of theelectrodes 14 in this skin region 38 will be described in greater detaillater. Opening of the pod sections 32 and 34 also makes the troughs 30readily accessible for receipt and routing of the electrode leads 12(see FIG. 8), which pass upward through the exposed skin region 38.

Closing of the pod sections 32 and 34 (see FIG. 10), captures theelectrode leads 12 within the mechanisms 60 in electrical connectionwith the circuitry 24 of the electronics pod 20. When in the closedcondition (as FIG. 10 shows), the pod sections 32 and 34 mate but stillallow visual inspection of the underlying skin region 38 through whichthe electrode leads 12 pass. As FIG. 5 shows, visual inspection of theunderlying skin region 28 through the pod 20 is still accommodated evenafter the carrier 16 is docked to the pod 20 (by viewing through anempty power input bay 40 of the carrier 16).

Desirably, closing of the pod sections 32 and 34 also cuts off excesslead wire at the end. Otherwise, the excess lead can be cut manually. Atthis time (see FIG. 11), a carrier 16 can be placed over the electronicspod 20, by snap-fitting the electronics pod 20 into an electronics bay22 of the carrier 16. An electrical connection region or contact 62 onthe pod 20 electrically couples to a mating connection region or contacton the carrier 16, to couple the circuitry 24 on the pod 20 to a powersource 42 carried by the carrier 16.

It should be appreciated that, in an arrangement where the electronicspod 20 is an integrated part of the carrier 16 (as shown in FIGS. 12Aand 12B), the carrier 16 itself can comprise the separable sections 32and 34. In this arrangement, one carrier section 34 can include anadhesive region 18, which will adhere the carrier 16 to the skin in anopened condition to allow routing of the electrode leads 12. Uponclosing the carrier sections 32 and 34, a pull-away strip 60 on theother carrier section 32 can be removed to expose another adhesiveregion to entirely secure the carrier 16 to the skin.

Alternative embodiments are possible. For example, a locking motion,coupling the electrode leads 12 to the electronics pod 20, can beaccomplished by a button, or a lever arm, or an alien drive that ispushed, or slid, or pulled, or twisted.

F. The Power Input/Communication Bay

Referring back to FIG. 3, the carrier 16 further includes a power inputbay 40. One function of the power input bay 40 is to releasably receivean interchangeable, and (desirably) disposable battery 42, e.g., analkaline or lithium battery. The battery 42 provides power to theelectronics pod 20. If desired (see FIG. 3), the power input bay 40 caninclude a hinged cover 44. FIG. 12B also shows the presence of abattery-receiving power input bay 40. Alternatively, the battery 42might form the cover without a hinge using a snap-fit mechanism tosecure the battery into the power input bay 40.

It is contemplated that, in a typical regime prescribed using theneuromuscular stimulation assembly 10, an individual will be instructedto remove and discard the battery 42 about once a day, replacing it witha fresh battery 42. This arrangement simplifies meeting the powerdemands of the electronics pod 20. The use of the neuromuscularstimulation assembly 10 will thereby parallel a normal, accustomedmedication regime, with the battery 42 being replaced in the samefrequency an individual administers medication in pill form. The battery42 may be provided in an over-molded housing to ease attachment andremoval.

The power input bay 40 can also serve as a communication interface. AsFIG. 13 shows, when free of a battery 42, the bay 40 can be used to plugin a cable 58 to an external programming device 46 or computer. Thiswill also be described later. This makes possible linking of theelectronics pod 20 to an external programming device 46 or computer.Through this link, information and programming input can be exchangedand data can be downloaded from the electronics pod 20.

In this way, the neuromuscular stimulation assembly 10 makes it possiblefor a care giver or clinician to individually program the operation of agiven electronics pod 20 to the extent permitted by the embedded,programmable code 26. It should be appreciated, of course, that insteadof using a cable interface, as shown, a wireless link (e.g., RFmagnetically coupled, infrared, or RF) could be used to place theelectronics pod 20 in communication with an external programming device46 or computer.

As FIG. 5 also shows, with the battery 42 removed and the cover (if any)opened, the underlying skin region 38, through which the percutaneouselectrode leads pass, can be readily viewed through the power input bay40.

G. The Electrodes and Their Implantation

The configuration of the electrodes 14 and the manner in which they areimplanted can vary. A representative embodiment will be described, withreference to FIGS. 14 to 16.

In the illustrated embodiment, each electrode 14 and lead 12 comprises athin, flexible component made of a metal and/or polymer material. By“thin,” it is contemplated that the electrode 14 should not be greaterthan about 0.5 mm (0.020 inch) in diameter.

The electrode 14 and lead 12 can comprise, e.g., one or more coiledmetal wires with in an open or flexible elastomer core. The wire can beinsulated, e.g., with a biocompatible polymer film, such aspolyfluorocarbon, polyimide, or parylene. The electrode 14 and lead 12are desirably coated with a textured, bacteriostatic material, whichhelps to stabilize the electrode in a way that still permits easyremoval at a later date and increases tolerance.

The electrode 14 and lead 12 are electrically insulated everywhereexcept at one (monopolar), or two (bipolar), or three (tripolar)conduction locations near its distal tip. Each of the conductionlocations is connected to a conductor that runs the length of theelectrode and lead, proving electrical continuity from the conductionlocation to the electronics pod 20. The conduction location may comprisea de-insulated area of an otherwise insulated conductor that runs thelength of an entirely insulated electrode. The de-insulated conductionregion of the conductor can be formed differently, e.g., it can be woundwith a different pitch, or wound with a larger or smaller diameter, ormolded to a different dimension. The conduction location of theelectrode may comprise a separate material (metal or conductive polymer)exposed to the body tissue to which the conductor of the wire is bonded.

The electrode 14 and lead 12 desirably possess mechanical properties interms of flexibility and fatigue life that provide an operating lifefree of, mechanical and/or electrical failure, taking into account thedynamics of the surrounding tissue (i.e., stretching, bending, pushing,pulling, crushing, etc.). The material of the electrode desirablydiscourages the in-growth of connective tissue along its length, so asnot to inhibit its withdrawal at the end of its use. However, it may bedesirable to encourage the in-growth of connective tissue at the distaltip of the electrode, to enhance its anchoring in tissue.

Furthermore, the desired electrode 14 will include, at its distal tip,an anchoring element 48 (see FIGS. 15 and 16). In the illustratedembodiment, the anchoring element 48 takes the form of a simple barb.The anchoring element 48 is sized and configured so that, when incontact with tissue, it takes purchase in tissue, to resist dislodgementor migration of the electrode out of the correct location in thesurrounding tissue. Desirably, the anchoring element 48 is preventedfrom fully engaging body tissue until after the electrode has beendeployed. The electrode is not deployed until after it has beencorrectly located during the implantation (installation) process, aswill be described in greater detail later.

In one embodiment, the electrode 14 and lead 12 can include a metalstylet within its core. Movement of the stylet with respect to the bodyof the electrode and/or an associated introducer (if used) is used todeploy the electrode by exposing the anchoring element 48 to bodytissue. In this arrangement, the stylet is removed once the electrode 14is located in the desired region.

In the illustrated embodiment (see FIGS. 14 and 15), each electrode 14is percutaneously implanted housed within electrode introducer 50. Theelectrode introducer 50 comprises a shaft having sharpened needle-likedistal tip, which penetrates skin and tissue leading to the targetedtissue region. The electrode 14 and lead 12 are loaded within a lumen inthe introducer 50, with the anchoring element 48 shielded from fulltissue contact within the shaft of the introducer 50 (see FIG. 14). Inthis way, the introducer can be freely manipulated in tissue in searchof a desired final electrode implantation site (see FIG. 14) beforedeploying the electrode (see FIG. 15) and withdrawing the introducer 50(see FIG. 16).

The electrode introducer 50 is insulated along the length of the shaft,except for those areas that correspond with the exposed conductionsurfaces of the electrode 14 housed inside the introducer 50. Thesesurfaces on the outside of the introducer 50 are electrically isolatedfrom each other and from the shaft of the introducer 50. These surfacesare electrically connected to a connector 64 at the end of theintroducer body (see FIGS. 14 and 15). This allows connection to astimulating circuit 66 (see FIG. 14) during the implantation process.Applying stimulating current through the outside surfaces of theintroducer 50 provides a close approximation to the response that theelectrode 14 will provide when it is deployed at the current location ofthe introducer 50.

The electrode introducer 50 is sized and configured to be bent by handprior to its insertion through the skin. This will allow the physicianto place an electrode 14 in a location that is not in an unobstructedstraight line with the insertion site. The construction and materials ofthe electrode introducer 50 allow bending without interfering with thedeployment of the electrode 14 and withdrawal of the electrodeintroducer 50, leaving the electrode 14 in the tissue.

II. Installation of the Neuromuscular Stimulation Assembly

Prior to installation, a clinician identifies a particular muscle and/orneural region to which a prescribed therapy using a neuromuscularstimulation assembly 10 will be applied. The particular types of therapythat are possible using the neuromuscular stimulation assembly 10 willbe described later. Once the particular muscle and/or tissue region isidentified, an electronics pod 20 (or a carrier 16 with integratedelectronics pod 20) is placed on the skin overlying the region (see FIG.6) and secured in place with pressure sensitive adhesive on the bottomof one-half of the pod/carrier. As previously stated, the adhesiveregion desirably contains a bacteriostatic sealant that prevents skinirritation or superficial infection, which could lead to prematureremoval.

As FIG. 6 shows, the electronics pod 20 (or carrier 16 with integratedelectronics pod 20) is placed on the skin in an opened condition, toexpose the skin region 38 between the pod (or carrier 16) sections 32and 34.

As FIGS. 7 to 10 show, the clinician proceeds to percutaneously implantthe electrodes 14 and lead 12, one by one, through the desired skinregion 38. While each electrode 14 is sequentially implanted, theelectrode introducer 50 applies a stimulation signal until a desiredresponse is achieved, at which time the electrode 14 is deployed and theintroducer 50 is withdrawn.

Upon implanting each electrode (see FIG. 7), the clinician routes eachelectrode lead 12 to a given trough 30. The clinician notes whichelectrode 14 is coupled to which channel.

After implanting all the electrode 14 and routing each lead 12 (see FIG.9), the clinician closes the electronics pod 20 (or carrier 16 withintegrated electronics pod 20) (see FIG. 10). In the former situation,the clinician snap-fits the carrier 16 over the electronics pod 20, asFIG. 11 shows. The adhesive region 18 on the carrier 16 secures thecarrier 16 to the skin. A battery 42 is placed into the power input bay40. The neuromuscular stimulation assembly 10 is ready for use.

Typically, as shown in FIG. 17, a container 52 holding a prescribednumber of replacement batteries 42 will be provided with theneuromuscular stimulation assembly 10, forming a neuromuscularstimulation system 54. Instructions for use 56 may accompany theneuromuscular stimulation system 54. The instructions 56 prescribe useof the neuromuscular stimulation assembly 10, including the periodicremoval and replacement of a battery 42 with a fresh battery 42. Thus,the instructions 56 prescribe a neuromuscular stimulation regime thatincludes a periodic recharging, via battery replacement, of theneuromuscular stimulation assembly 10 in the same fashion thatpill-based medication regime directs periodic “recharging” of themedication by taking of a pill. In the context of the neuromuscularstimulation system 54, a battery 42 becomes the therapeutic equivalentof a pill (i.e., it is part of a user action taken to extend treatment).

As FIG. 13 shows, external desktop or handheld (desirably also batterypowered) preprogrammed instruments 46 can be used to program stimulusregimes and parameters into the neuromuscular stimulation assembly 10,or to download recorded data from the neuromuscular stimulation assembly10 for display and further processing. The instruments 46 cancommunicate with the neuromuscular stimulation assembly 10, e.g., by acable connection, by radio frequency magnetic field coupling, byinfrared, or by RF wireless. As before described, the power input bay 40can additionally comprise a communications interface, that is coupled toa communications cable 58 connected to the instrument 46. Thecommunications cable 58 provides power to the neuromuscular stimulationassembly 10 during programming, as well as communications with thecircuitry 24 of the neuromuscular stimulation assembly 10. The externalprogramming instrument 46 can also be a general purpose personalcomputer or personal digital device fitted with a suitable customprogram and a suitable cable or interface box for connection to thecommunications cable 58.

The programming instruments 46 allow a clinician to customize theprogrammable code 26 residing in an individual neuromuscular stimulationassembly 10 according the specific needs of the user and the treatmentgoals of the clinician. The neuromuscular stimulation assembly 10 can,once customized, be disconnected from the programming system, allowingportable, skin-worn operation, as already described.

III. Representative Use of the Neuromuscular Stimulation Assembly/System

A. Overview

The neuromuscular stimulation assembly 10 and/or neuromuscularstimulation system 54, as described, make possible the providing ofshort-term therapy or diagnostic testing by providing electricalconnections between muscles or nerves inside the body and stimulusgenerators or recording instruments mounted on the surface of the skinoutside the body. The programmable code 26 of the neuromuscularstimulation assembly 10 and/or neuromuscular stimulation system 54 canbe programmed to perform a host of neuromuscular stimulation functions,representative examples of which will be described for the purpose ofillustration.

B. Continuous Active Motion (CAM)

CAM using the neuromuscular stimulation assembly 10 and/or neuromuscularstimulation system 54 provides the stimulus necessary to improvecardiovascular endurance, muscular strength, and neurologiccoordination. Through the CAM, this active-assisted exercise is atechnique used to assist the active, voluntary movement of the targetlimb, thereby decreasing the amount of strength needed to move thejoints. This technique has been proven effective in increasing thestrength of individuals beginning at very low levels. Therapeuticbenefits include reduced inflammation of the affected joint, improvedrange of motion, pain relief, and enhanced functional mobility. CAM isdifferentiated from continuous passive motion (CPM), which is themovement of a joint or extremity through a range of motion withoutvoluntary movement of the limb.

C. Post Trauma Anti-Scarring Treatment

Post Surgical scarring, (e.g. posterior approaches to the spine), is thebane of most Orthopedic or Neurosurgical procedures. Scarring oradhesion, that is a fibrous band of scar tissue that binds togethernormally separate anatomical structures during the healing process, canbe one of the single greatest reasons for patient's surgical “failure”.A terrific and well executed operation by a gifted surgeon can be wastedin a short time due to the body's tendency to scar during post surgicalhealing. By applying the neuromuscular stimulation assembly 10 and/orneuromuscular stimulation system 54 to the muscles or nerves in thespecific surgical wound area, relatively small motions may preventscarring, while the tissue is healing.

D. Temporary, Non-Surgical Diagnostic Assessment

Prior to the administering of a specific permanent implantedneuromodulation or neurostimulation system, (e.g. urinary incontinence,vagal nerve stimulation for epilepsy treatment, spinal cord stimulatorsfor pain reduction), the neuromuscular stimulation assembly 10 and/orneuromuscular stimulation system 54 can be applied to provide thephysician and their patient with some assurance that through thetemporary stimulation of the end organ, the treatment is viable. Thiswould allow the physician to screen patients that may not be candidatesfor the permanent treatment, or otherwise, may not find the effect ofthe treatment to worth the effort of the surgical implantation of apermanent system.

E. Neuroplasticity Therapy

Individuals with neurological deficits, such as stroke survivors orthose with multiple sclerosis may lose control of certain bodilyfunctions. The brain, may, through a process called “neuroplasticity,”recover functionally, by reorganizing the cortical maps or spinalcord-root interfaces and increasing auxiliary blood supply, whichcontributes to neurological recovery. By applying the neuromuscularstimulation assembly 10 and/or neuromuscular stimulation system 54 toaffected areas of the body and providing excitation and input to thebrain, a neuroplastic effect may occur, enabling the brain to re-learnand regain control of the lost function.

F. Anti-Spasm Therapy

The use of temporary neurotoxins (e.g. botox) has become widespread intreating severe muscles spasms from cerebral palsy, head injury,multiple sclerosis, and spinal cord injury to help improve walking,positioning and daily activities. Botox can also be used to treat eyeconditions that cause the eye to cross or eyelid to blink continuously.It is also purported to eliminate wrinkles by limiting the ageingprocess. The neuromuscular stimulation assembly 10 and/or neuromuscularstimulation system 54 may be used as an alternative means of reducingthe spasticity without having to temporarily paralyze the nerves andmuscles. The neuromuscular stimulation assembly 10 and/or neuromuscularstimulation system 54 also may be useful in treating TMJ(temporomandibular joint) disorders, which are manifested by pain in thearea of the jaw and associated muscles spasms and limitations in theability to make the normal movements of speech, facial expression,eating, chewing, and swallowing.

G. Chronic or Temporary Pain Therapy

Localized pain in any area of the body can be treated with theneuromuscular stimulation assembly 10 and/or neuromuscular stimulationsystem 54 by applying it directly to the effected area. Theneuromuscular stimulation assembly 10 and/or neuromuscular stimulationsystem 54 works by interfering with or blocking pain signals fromreaching the brain.

H. Post-Surgical Reconditioning

Recovery of strength and muscle function following surgery can bepromoted using the neuromuscular stimulation assembly 10 and/orneuromuscular stimulation system 54. The assembly 10 and/or system 54can be prescribed post-operatively and installed in association with theappropriate muscles regions to provide a temporary regime of musclestimulation, alone or in conjunction with a program of active movements,to aid an individual in recovering muscle tone, function, andconditioning following surgery.

I. Thromboembolism Prophyllaxis

The neuromuscular stimulation assembly 10 and/or neuromuscularstimulation system 54 can provide anti-thrombosis therapy by stimulatingthe leg muscles which increases venous return and prevent blood clotsassociated with pooling of blood in the lower extremities. Routinepost-operative therapy is currently the use of pneumatic compressioncuffs that the patients wear on their calves while in bed. The cuffscycle and mechanically compress the calf muscles, thereby stimulatingvenous flow. Patients hate this, but every surgical bed in the hospitalnow has this unit attached to it. This same effect could be duplicatedby installing a neuromuscular stimulation assembly 10. Prophyllaxis ismost effective if begun during surgery, as many, if not most clots, formduring surgery. Thus, it is desirable to install a neuromuscularstimulation assembly 10 and begin use of the neuromuscular stimulationsystem 54 at the beginning of an operation.

J. Treatment of Osteoporosis

Cyclic muscle contraction loads bone sufficiently to prevent (andpossibly) reverse osteoporosis. The effectiveness of such treatment isknown to be frequency dependent. The neuromuscular stimulation assembly10 and/or neuromuscular stimulation system 54 can be programmed tostimulate muscles at the appropriate frequency to prevent/reverseosteoporosis.

Various features of the invention are set forth in the following claims.

1. A method of providing a neurostimulation function comprising thesteps of providing a percutaneous electrode, the percutaneous electrodecomprising a flexible body including an electrically conductive region,a tissue penetrating region for implanting the electrically conductiveregion in tissue, a percutaneous lead electrically coupled to theelectrically conductive region, and an anchoring element on the flexiblebody to resist movement of the percutaneous electrode within tissue,inserting the percutaneous electrode within an introducer that shieldsthe anchoring element from contact with tissue, the introducer includingan electrically isolated area that correspond to the electricallyconductive region of the flexible body, implanting the percutaneouselectrode while inserted within the introducer, to place thepercutaneous electrode in a desired location within tissue, withdrawingthe introducer to place the anchoring element in contact with tissue,thereby resisting movement of the percutaneous electrode from thedesired position, providing a carrier sized and configured to be worn bythe patient, the carrier also being sized and configured to hold a powersource that can be released and replaced, the carrier including anelectronics pod, the electronics pod including circuitry configured togenerate a stimulation pulse, providing instructions prescribing therelease and replacement of the power source, electrically engaging thepercutaneous lead to the carrier to electrically couple the electricallyconductive region to the electronics pod, and activating the circuitryto generate a stimulation pulse to percutaneously apply the stimulationpulse to the tissue to provide the neurostimulation function.
 2. Amethod according to claim 1 wherein the electrically isolated area iselectrically coupled to a connector on the introducer to allow theelectrically isolated area to be coupled to a stimulating circuit.
 3. Amethod according to claim 2 further including, during the implantingstep, a step of coupling the introducer to a stimulating circuit toprovoke a tissue stimulation response to place the percutaneouselectrode in the desired location.